Rasch analysis of Chinese cerebral palsy quality of life for children (C-CP QOL-Child)

The Chinese Cerebral Palsy Quality of Life for Children (C CP QOL-Child) is the first instrument developed to measure quality of life of (QOL) children with cerebral palsy in Chinese speaking populations. The aim of the study was to examine the psychometric properties of C CP QOLChild using Item Response Theory Models. We were particularly interested to know how intervention strategies could be designed for individuals based on the item scores. 145 primary caregivers (mostly mothers; mean age: 39.2) and their children with cerebral palsy (age: 4-12) were invited to complete the C CP QOL-Child questionnaire. Data were analyzed using Rasch analysis. The results indicated that item difficulty estimates were aligned with person ability values, indicating that the items in the scale generally demonstrated an appropriate depth and width for measuring QOL of persons in the target population. The results in study 2 (Part II) also showed that after dropping the 8 items in the dimension pain and impact of disability in the 65-item parent proxy scale, the revised 57-item scale exhibits unidimensionality (separation index = 4.43, r = 0.95); hence the total score computed from the 57 items adequately reflects the level of QOL of the child as perceived by the caregiver. We further found that the Rasch item difficulty estimates demonstrated an overall item hierarchy; hence therapists can expect a pattern of performance by a child with CP that is based on the established order of item difficulty. Hence, the hierarchical structure identified in the study may be useful for designing tailor-made interventions with an aim of improving QOL. All rights reserved.